The present invention relates to a carrier for semiconductor wafers and the method of manufacture of the carrier and more particularly to such a carrier for use in elevated temperature processing of semiconductor wafers.
In the formation of semiconductor "boats" or carriers for use in high temperature semiconductor processing, round quartz rod has been used almost exclusively in the past. Whenever square rod was utilized the boat or carrier proved to be relatively expensive since the square rod was necessarily machined from larger quartz billets. Round quartz rod is extruded and since it is hot formed contains considerable internal stress in the round rod shape. Consequently, when "boats" are fabricated of round or square rod, if internal stress is present in the rod, deformation of the carrier takes place during high temperature processing of the carried semiconductor wafers and the carrier is useful only for a limited number of such processes. The deformation causes uncontrolled internal stress to be imposed upon the carried semiconductor wafers with consequent adverse effects upon the operating characteristics of the processed semiconductor elements.
A semiconductor wafer carrier or semiconductor boat is desirable which has a long life in terms of the number of elevated temperature processes to which it may be exposed and which is rigid at elevated temperatures exhibiting minimal dimensional change due to plasticity or "sag" at high temperature or due to relief of internal stress in the component parts of the carrier.